It is a known problem with school buses that as children are let off after school at the various stops that the school bus makes on its route to drop off children, that bus driver supervision of the children surrounding the bus is particularly difficult to ensure that no children have slipped underneath the bus either accidentally or intentionally. This is particularly difficult since several children may be getting off the bus at the same time and to monitor the movements of all children getting off the bus is virtually impossible, and even with the best mirror systems, there is no guarantee that a child does not slip under the bus and out of the view of the mirror system.
As early as 1959 in British Patent Specification 809,624, it was known to provide safety devices fitting in front of wheels on buses and cars in order to provide a barrier preventing a pedestrian from being caught underneath the wheels of the vehicle. These devices were fixed in nature, and were not particularly practical. U.S. Pat. Nos. 4,688,824 and 4,877,266 are examples of more recent safety devices for school buses which serve to prevent children from being caught under the wheels which are of a more practical construction. U.S. Pat. No. 4,688,656 describes a barrier safety device in which contact with the device activates means for turning off the motor vehicle.
In the prior art systems, no effective combination of a safety barrier and a detecting means to indicate the presence of a person or an object in closed proximity or in contact with the safety barrier has been constructed. It is important for such safety barriers to completely eliminate the possibility that a child or object be caught under the wheels and also to prevent that the child be pushed or dragged.